我的組合框選定的值綁定不會以雙向方式迴流數據綁定

Question

使用簡單MVVM框架創建簡單的Silverlight 4.0 LOB應用程序。

我有一個僱員列表視圖，顯示列表中的所有員工，我有我的EmployeeListViewModel一些特性如下：

private Grade selectedGrade; 
    public Grade SelectedGrade 
    { 
     get { return selectedGrade; } 
     set 
     { 
      selectedGrade = value; 
      NotifyPropertyChanged(m => m.SelectedGrade); 
     } 
    } 

    private Religion selectedReligion; 
    public Religion SelectedReligion 
    { 
     get { return selectedReligion; } 
     set 
     { 
      selectedReligion = value; 
      NotifyPropertyChanged(m => m.SelectedReligion); 
     } 
    } 
    private ObservableCollection<Grade> grades; 
    public ObservableCollection<Grade> Grades 
    { 
     get { return grades; } 
     set 
     { 
      grades = value; 
      NotifyPropertyChanged(m => m.Grades); 
     } 
    } 

    private ObservableCollection<Religion> religions; 
    public ObservableCollection<Religion> Religions 
    { 
     get { return religions; } 
     set 
     { 
      religions = value; 
      NotifyPropertyChanged(m => m.Religions); 
     } 
    } 
    private ObservableCollection<Department> departments; 
    public ObservableCollection<Department> Departments 
    { 
     get { return departments; } 
     set 
     { 
      departments = value; 
      NotifyPropertyChanged(m => m.Departments); 
     } 
    } 
    private Employee selectedEmployee; 
    public Employee SelectedEmployee 
    { 
     get { return selectedEmployee; } 
     set 
     { 
      selectedEmployee = value; 
      SetCanProperties(); 
      NotifyPropertyChanged(m => m.SelectedEmployee); 
     } 
    } 
    private ObservableCollection<Employee> employees; 
    public ObservableCollection<Employee> Employees 
    { 
     get { return employees; } 
     set 
     { 
      employees = value; 
      NotifyPropertyChanged(m => m.Employees); 
     } 
    } 
    private Department selectedDepartment; 
    public Department SelectedDepartment 
    { 
     get { return selectedDepartment; } 
     set 
     { 
      selectedDepartment = value; 
      NotifyPropertyChanged(m => m.SelectedDepartment); 
     } 
    } 

現在在我看來，我有一個按鈕，在我的員工來編輯選定員工它開創了一個新的子窗口與EmployeeDetails編輯

EmployeeListViewModel viewModel; 
    public EmployeeListView() 
    { 
     InitializeComponent(); 
     viewModel = (EmployeeListViewModel)DataContext; 
    } 

這裏列出的是編輯員工方法

private void editItemButton_Click(object sender, RoutedEventArgs e) 
    { 
     // Exit if no product selected 
     if (viewModel.SelectedEmployee == null) return; 

     // Create a product detail model 
     EmployeeDetailViewModel detailModel = 
      new EmployeeDetailViewModel(viewModel.SelectedEmployee); 
     // set comboboxes !! 

     detailModel.Departments = viewModel.Departments; 
     detailModel.Religions = viewModel.Religions; 

     detailModel.Grades = viewModel.Grades; 

     // Start editing 
     detailModel.BeginEdit(); 

     // Show EmployeeDetail view 
     EmployeeDetailView itemDetail = new EmployeeDetailView(detailModel); 
     itemDetail.Closed += (s, ea) => 
     { 
      if (itemDetail.DialogResult == true) 
      { 
       // Confirm changes 

       detailModel.EndEdit(); 
      } 
      else 
      { 
       // Reject changes 
       detailModel.CancelEdit(); 
      } 
     }; 
     itemDetail.Show(); 
    } 

現在

我的詳細信息子視圖我有這個Constractor

public EmployeeDetailView(EmployeeDetailViewModel viewModel) 
    { 
     InitializeComponent(); 
     DataContext = viewModel; 
    } 

，這裏是我的DetailsViewModel constractor

public EmployeeDetailViewModel(Employee model) 
    { 
     base.Model = model; 
    } 
     private ObservableCollection<Religion> religions; 
    public ObservableCollection<Religion> Religions 
    { 
     get { return religions; } 
     set 
     { 
      religions = value; 
      NotifyPropertyChanged(m => m.Religions); 
     } 
    } 

    private ObservableCollection<Grade> grades; 
    public ObservableCollection<Grade> Grades 
    { 
     get { return grades; } 
     set 
     { 
      grades = value; 
      NotifyPropertyChanged(m => m.Grades); 
     } 
    } 
    private ObservableCollection<Department> departments; 
    public ObservableCollection<Department> Departments 
    { 
     get { return departments; } 
     set 
     { 
      departments = value; 
      NotifyPropertyChanged(m => m.Departments); 
     } 
    } 

畢竟這現在來結合我有三個組合框 的部門，宗教和等級（這是我員工表中的外鍵）

<ComboBox ItemsSource="{Binding Departments}" DisplayMemberPath="DepartmentName" SelectedValue="{Binding Model.Emp_Department, Mode=TwoWay}" SelectedValuePath="DepartmentId"/> 
    <ComboBox ItemsSource="{Binding Grades}" DisplayMemberPath="GradeName" SelectedValue="{Binding Model.Emp_Grade, Mode=TwoWay}" SelectedValuePath="GradeId"/> 

等等..問題是，只有部門組合框正在更新源值，當我更改它的值

和其他組合框不..即使綁定語句完全相同！

很抱歉寫這麼多..但任何人都可以幫助我嗎？

非常感謝

Answer 1

很遺憾，您MVVM分離是有點搞砸了，你是從直接查看到底層模型（意味着視圖模型的任何業務邏輯/確認）結合被繞過。

但是，你似乎一切準備就緒，所以我會建議如下：

更改您的XAML到這個（注意，從的SelectedValue到的SelectedItem的變化）：二傳手內

<ComboBox ItemsSource="{Binding Departments}" DisplayMemberPath="DepartmentName" SelectedItem="{Binding SelectedDepartment, Mode=TwoWay}"/> 
<ComboBox ItemsSource="{Binding Grades}" DisplayMemberPath="GradeName" SelectedItem="{Binding SelectedGrade, Mode=TwoWay}"/> 

然後SelectedDepartment/SelectedGrade屬性中，執行任何必需的驗證，然後將所選項目的ID寫入（detail）模型中的屬性。

希望它有幫助。

Answer 2

那麼這裏是我做我的連擊：

<ComboBox ItemsSource="{Binding Path=ListPeople, UpdateSourceTrigger= PropertyChanged}" SelectedItem="{Binding Path=SelectedPerson, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" DisplayMemberPath="FirstName"/> 

，並在我的視圖模型：

private ObservableCollection<Person> listPeople = new ObservableCollection<Person>(); 

public IEnumerable<Person> ListPeople 
    { 
     get { return this.listPeople; } 
    } 

public Person SelectedPerson 
    { 
     get { return selectedPerson; } 
     set 
     { 
      selectedPerson = value; 
      if (selectedPerson != null) 
      { 
       NextToPayID = selectedPerson.PersonID; 
      } 
      base.RaisePropertyChanged("SelectedPerson"); 
     } 
    } 

看到，如果你可以用它來幫助！